Analysis On The Kinematics Characteristics Of Starting Technique Of Tianjin Elite Male Breaststroke Athletes

As the beginning of swimming competition,departure has always been attached great importance by athletes and coaches,especially in the short distance events,the departure distance accounts for 30% of the 50 m distance and the departure performance accounts for 25% of the 50 m result.Therefore,for 0.01 seconds can determine the outcome of swimming competition,excellent starting technology is the most important in the competition,which is undisputed.In the six stages of the starting technology,the underwater taxiing stage is the longest,and the resistance in the water entry and underwater taxiing stage is the largest.The research on "water entry technology" and "drag reduction technology in the water entry taxiing stage" will be paid more and more attention by athletes and coaches.In this paper,by using the methods of literature,experiment,image analysis and mathematical statistics,the best breaststroke athletes in Tianjin are selected.SJL and c.yb are the research objects.The kinematics and dynamics of the above water and under water technology are analyzed.Pas-s system is used to obtain the time,displacement,speed,angle and peak force of athletes.Based on the analysis of the parameters of s.jl and c.yb,the following conclusions are drawn:1.In the stage of preliminary postures,s.jl is longer than c.yb.It is suggested that s.jl move forward the position of body center of gravity to shorten the horizontal displacement and time.2.In the stage of leaving the stage,Tianjin elite breaststroke athletes lift their upper limbs too high,and the vertical force is greater than the horizontal force,resulting in the angle of leaving the stage is too large;the peak force value is low,so it is suggested to strengthen the strength training,fully develop the pulling effect of waving and the pedaling force of both feet,and control the direction of force.3.In the stage of taking off,the excellent breaststroke swimmers in Tianjin have a long distance to enter the water and poor control ability of body posture in the air.It is suggested to strengthen the exercise of core strength and the control ability of body in flight.4.In the water entry stage,the angle of entry of Tianjin excellent breaststroke athletes and world excellent breaststroke athletes is greater than 45 degrees;the smallest range of entry is s.jl,followed by the world excellent breaststroke athletes with good drag reduction technology,c.yb is the largest,s.jl;but the speed of entry is not the fastest.5.In the underwater gliding stage,the maximum depth of entry of Tianjin elite breaststroke swimmers is shallower than that of the world elite breaststroke swimmers;s.jl is earlier than c.yb in the first stroke of butterfly leg,and the distance is close;s.jl is longer than c.yb in the time of 5m,and s.jl is shorter than c.yb in the time of 7m and 10m;s.jl is slightly larger than c.yb in the segmented speed;in the underwater gliding stage,two athletes should strengthen their body control ability.6.In the water stage,the excellent breaststroke swimmers in Tianjin have a long distance out of water,a long time of 15 meters,and a slow movement rhythm in the underwater sliding stage.It is suggested to strengthen the joint practice of underwater sliding technology,and master a reasonable joint rhythm of technical movements.